Yes, people have freedom to make changes.

We have a mind and a body and we are given the freedom in the best of circumstances to make whatever changes we would like. That does not mean that all changes we might make are good for us or for those around us. That is where critical thinking needs to be enhanced so that we really do the things that enhance rather than hinder us.

No, there are many means that are not justified.

The only justified means to change the mind or body are means that involve no damage to either the recipient or anyone else. "Any means possible" covers quite a large area. Surely it is not justified to steal body parts from another to enhance your own. Surely it is not justified to change a person's mind through blackmail or intimidation.